The present disclosure relates to an image forming apparatus including an exhaust duct collecting particulates and the exhaust duct.
In an image forming apparatus, particulates, such as an ink or a toner, may be floated and scattered inside the apparatus. In order to collect the floated particulates, the image forming apparatus includes, for example, a fan, an exhaust duct and a filter. In the image forming apparatus, an air inside the apparatus is sucked by a fan, guided to the filter by the exhaust duct and cleaned by the filter, and then, ejected outside the apparatus.
As one example of the image forming apparatus, an inkjet printing apparatus is configured to include a noise silencer removing an ink particle with a filter. Inside the noise silencer, a baffle wall is arranged and formed so as to partially flow an air and to facilitate flowing some air on the surface.
Another example of the image forming apparatus is configured to include a developer sucking device sucking and collecting a developer floated in developing. The developer sucking device has an air duct and the duct is provided with libs respectively arranged to one inside wall face and another inside wall face facing to each other. One lib is shifted from another lib in a flowing direction of the air duct, i.e., these libs are alternately arranged to compose one developer collecting box. An area of an inflow port of the developer collecting box is 10-25 percent of a cross-section area of an air path of the air duct.
A further example of the image forming apparatus is configured to include a developing device to which a floated toner collecting device. The floated toner collecting device has a sucking duct having a plurality of toner catching protruded parts inside. Each toner catching protruded part is protruded from an upstream side end to a downstream side end in an air current direction in the sucking duct and upward from a bottom wall face in the duct. The toner catching protruded part has a difference recessed to the bottom wall face in the duct at the downstream side end.
However, in the above-mentioned one example's image forming apparatus, in order to make the baffle wall function as the filter, it is necessary to configure a plurality of the baffle walls so as to individually interrupt a half or more of the air path cross-section in the noise silencer so that many air hits against the plurality of the baffle walls. Therefore, since the air flowing in the noise silencer receives great pressure drop by the baffle walls, it is necessary to apply the fan having large air volume. In addition, since the fan having large air volume is used, there is a possibility of loudening noise and increasing energy consumption. Moreover, since this baffle wall has a vertical shape and is formed to facilitate flowing of the air on the surface, it is difficult to generate vortex collecting the particulates.
In the above-mentioned other example's image forming apparatus, the developer collecting box is configured by alternating two libs bent in a U-shape. However, in this configuration, the libs interrupt a half or more of the air path cross-section in the air duct. Therefore, since the air flowing in the air duct receives great pressure drop by the libs, it is necessary to apply the fan having large air volume and there is a possibility of loudening noise and increasing energy consumption by the fan having large air volume. Moreover, since this lib has a vertical shape, it is difficult to generate vortex collecting the particulates.
Incidentally, if a capacity of the exhaust duct were increased in order to decrease the pressure drop of the air flowing, it is necessary to secure wide space used for arrangement of the exhaust duct inside the image forming apparatus, and then, the apparatus is enlarged.
In the above-mentioned further example's image forming apparatus, the toner catching protruded part protruded on the inside wall face of the sucking duct is formed with a right angled triangle cross-section higher at the upwind side so that vortex is generated in the vicinity of the right angled part and the particulates are accumulated. However, in an air path generated in this sucking duct, the air is directly flowed from an inlet port to an outlet port without receiving an influence of the toner catching protruded part. In this air path, the particulates are not decelerated and are directly sucked to the filter. Therefore, there are possibilities that the particulates hit the filter to damage the filter and the filter is clogged by the particulates. Incidentally, if the fan having small air volume were applied in order to prevent such a phenomenon, since the air volume is insufficient, the vortex is not generated in the toner collecting protruded part and the particulates cannot be collected in the duct.
In addition, if the fan having small air volume were applied in order to prevent such a phenomenon, there is a possibility of insufficiently collecting the particulates inside the apparatus. Moreover, for example, if the fan having small air volume were applied in order to absorb a sheet to a conveyance belt in the image forming apparatus, there is a possibility of inappropriately absorbing the sheet and inappropriately conveying the sheet.